Connection Pool

Connection queue information shows the number of sessions in the queue,
and the average delay before the connection is accepted.

If your system has extra CPU cycles, keep incrementally increasing connection
pool settings and monitor performance after each incremental increase. When
performance saturates (stops improving), then stop increasing the settings.

Connection pool settings that affect performance are:

Max Pending Count

Queue Size

Max Pending Count

Max Pending Count specifies the maximum number of pending connections
on the listen socket. Adjust Max Pending Count only when there is a heavy
load on the system. For low to medium loads, the default will be acceptable.

After observing system behavior, change the value accordingly, otherwise
the server will start dropping connections. Connections that time out on a
listen socket whose backlog queue is full will fail. If Max Pending Count
is close to the limit, increase the maximum connection queue size to avoid
dropping connections under heavy load.

Queue Size

Queue Size specifies the number of outstanding (yet to be serviced)
connections that the server can have. For heavily loaded systems (with many
users) that have limited request processing threads, adjust this setting to
a higher value.

Note –

Setting the connection queue size too high can degrade server
performance. It was designed to prevent the server from becoming overloaded
with connections it cannot handle. If the server is overloaded, increasing
the connection queue size will increase the latency of request handling, and
the connection queue will fill up again.

Send Buffer Size

Specifies the size (in bytes) of the send buffer used by sockets.

Receive Buffer Size

Specifies the size (in bytes) of the receive buffer used by sockets.

The Send Buffer Size and Receive Buffer Size are the buffer sizes allocated
for output and input buffers, respectively. To tune these parameters, increase
them methodically and observe the impact on performance. Stop increasing the
values when performance saturates (does not increase significantly).